Living body communication transmits and receives communication data through living bodies including a human body. Such communication attracts attention. The living body communication is expected to be used in such fields as medical treatment/health care, short-distance radio, in-vehicle radio, and entertainment. The living body communication is capable of reducing power consumption more substantially than before.
Two electrodes are provided to a communication apparatus for the living body communication that uses a living body as a part of a transmission line. One of the two is a signal electrode connected to a signal line, and the other is a reference potential electrode connected to the earth potential of the communication apparatus having reference potential. Signal electrodes are connected to each other mainly through a living body. Reference potential electrodes connected to each other mainly through a space or the earth. Thereby, the communication apparatus transmits a potential difference between the signal electrode and the reference potential electrode.
Covering the communication apparatus with a housing is effective to enhance reliability of the communication apparatus that communicates through a living body. When signal electrodes are packed within the housing, a capacity coupling between a living body and a signal electrode is formed through the housing. Therefore, the communication apparatus results in lowering of the receiving sensitivity.